This invention relates generally to a portable electric fan and, more particularly, to a portable electric window fan.
Portable electric fans are used extensively to reduce personal discomfort caused by excessive temperatures. Some portable electric fans are designed specifically for mounting in open windows of inhabited enclosures and are typically operable to either exhaust air from the enclosure or direct outside air thereinto. Although generally quite efficient for establishing desirable air circulation between inside and outside of a particular enclosure, prior window fans have failed to provide fully satisfactory air flow patterns because of positional mounting limitations. For example, conventional window fans do not provide the variety of air flow distribution patterns furnished by portable floor or table fans that can function in a wider variety of positions. Also, the requirement in window fans for oppositely directed inlet and outlet openings presents problems not present in other environmental conditioning devices such as air conditioners.
In efforts to extend air circulation patterns, some prior fans have been provided with automatically movable frames. For example, U.S. Pat. No. 2,786,627 discloses a portable fan with an oscillating fan blade. However, such prior portable fans have not been capable of producing efficient air movement through an open window.
The object of this invention, therefore, is to provide an improved, more versatile portable window fan.